Flexible clamping device

Abstract

The utility model discloses a flexible clamping device. The device comprises a flexible clamping jaw, a control system and an upper computer, the flexible clamping jaw comprises two symmetrically-arranged clamping jaw bodies, the bottoms of the clamping jaw bodies are fixed to a fixing plate, clamping jaw fingers are arranged at the tail ends of the upper portions of the clamping jaw bodies, and piezoelectric films are pasted to the outer sides of the clamping jaw fingers. And the control system comprises a controller, and an air source driver, a filtering and amplifying circuit and a power supply which are respectively connected with the controller. The driver outputs a driving signal to drive the clamping jaw body of the flexible clamping jaw to drive the two clamping jaw fingers to be relatively close to or separated from each other to realize clamping or releasing; the filtering and amplifying circuit is connected with the piezoelectric films on the outer sides of the clamping jaw fingers to collect voltage feedback signals representing the magnitude of the clamping force, and the voltage feedback signals are output to the controller for closed-loop control after being processed. The utility model provides a novel flexible clamping device by designing a circuit structure and a clamping jaw structure, so as to solve the problem of grabbing and placing tiny objects.

Description

Technical Field

[0001] This utility model relates to a flexible clamping device for grasping and placing small objects. Background Technology

[0002] Flexible clamping is a clamping technology that can automatically adjust and adapt to the shape, size, and characteristics of different workpieces. It achieves precise, stable, and flexible clamping of workpieces through the use of special materials, structures, and control strategies. Flexible clamping technology is characterized by high adaptability, flexibility, and safety. High adaptability is reflected in its ability to handle workpieces of various shapes, sizes, and materials, effectively clamping both regular geometric shapes and complex curved surfaces, as well as fragile or soft objects. Flexibility is reflected in the ability to quickly adjust clamping parameters and methods according to different production needs, adapting to changes in the production line and reducing equipment downtime and changeover costs. Safety is reflected in the protection of the workpiece during clamping, preventing damage due to excessive clamping force or improper operation, thus reducing production costs.

[0003] Flexible gripping technology is widely used in manufacturing, biomedicine, and agri-food industries. In manufacturing, it is widely used in machining, assembly, and welding processes to grip various components, such as automotive engine blocks and electronic components, improving production efficiency and product quality. In the biomedical industry, it has important applications in surgical robots and rehabilitation equipment. For example, the flexible gripping mechanism in surgical robots can precisely manipulate surgical instruments, improving surgical accuracy and safety. In the agri-food industry, for irregularly shaped and easily deformable foods, such as fruits, vegetables, and bread, flexible gripping technology can grasp and package them without damaging them, ensuring food quality and hygiene.

[0004] While flexible clamping technology offers numerous advantages, it also suffers from several drawbacks, primarily including limited clamping force, poor stability, and low repeatability. The clamping force of a flexible clamp relies mainly on the elastic deformation and friction of the material, resulting in a relatively smaller clamping force compared to rigid clamps. The structure of a flexible clamp is relatively complex and susceptible to external factors such as temperature changes and vibrations, which can alter its performance and affect clamping stability. Due to the deformable nature of flexible materials, the clamp may not fully return to its initial state after each workpiece clamping and release, thus impacting its repeatability. Utility Model Content

[0005] The purpose of this invention is to provide a flexible clamping device by designing a circuit structure and a gripper structure to solve the problem of grasping and placing small objects.

[0006] The technical solution of this utility model is as follows:

[0007] A flexible clamping device includes flexible grippers and a control system;

[0008] The flexible gripper includes two symmetrically arranged gripper bodies. The bottom of the gripper body is fixed to a fixed plate. The upper end of the gripper body is provided with gripper fingers, and a piezoelectric film is attached to the outside of the gripper fingers.

[0009] The control system includes a controller and connected air source driver, filter amplifier circuit, and power supply for the controller, air source driver, and filter amplifier circuit. The driver outputs a drive signal to drive the gripper body of the flexible gripper, causing the two gripper fingers to move closer or further apart to achieve gripping or release. The filter amplifier circuit is connected to the piezoelectric film on the outside of the gripper fingers. A voltage feedback signal characterizing the magnitude of the gripping force is acquired, processed, and output to the controller for closed-loop control.

[0010] The gripper body is a rubber cavity, and the cavity is equipped with an air passage connector, which is connected to the air source driver through an air pipe.

[0011] The air source driver can be an active or passive air source driver.

[0012] The gripper fingers are made of alloy sheets that bend and deform when gripping an object.

[0013] The filtering and amplification circuit includes: terminals ADC1 and AGND connected to the two ends of the piezoelectric film; terminal ADC1 is also grounded through TVS diode D1; two voltage divider branches are connected in parallel between terminals ADC1 and AGND; the two voltage divider branches respectively lead out two voltage signals to the two input terminals 1IN+ and 1IN+ of operational amplifier U1; the parallel connection of 1OUT and 1IN- of operational amplifier U1 outputs the CPU-ADC1 voltage follower signal; the parallel connection of 2OUT and 2IN- of operational amplifier U1 outputs the CPU-ADC2 voltage follower signal; the two voltage follower signals are connected to the controller; the VDD terminal of operational amplifier U1 is grounded through capacitor C1, and the GND terminal is grounded.

[0014] Each voltage divider branch of the filter amplifier circuit consists of two resistors connected in series: resistors R1 and R3 are connected in series, and resistors R2 and R4 are connected in series.

[0015] The piezoelectric film is provided with a terminal block, which is connected to the terminal blocks ADC1 and AGND of the filter amplifier circuit.

[0016] The controller is a microcontroller; the power supply is a DC-DC module that provides +12V power to the controller, +24V power to the air source driver, and +5V power to the filter amplifier circuit.

[0017] The flexible gripper is mounted on the fixed plate by fixing plate bolts; the gripper fingers are mounted on the gripper body by finger fixing bolts.

[0018] The bottom fixing plate of the flexible gripper of the flexible clamping device is also fixed to the end of the robotic arm by bolts. The movement of the robotic arm drives the flexible clamping device to move to the vicinity of the target object to be clamped.

[0019] The beneficial effects of this utility model are as follows:

[0020] 1. The flexible clamping device of this utility model has a piezoelectric thin film sensor and a feedback circuit control structure, which can monitor and adjust the clamping force in real time to ensure that the clamping force is always within a suitable range, and avoid problems such as damage or slippage of objects due to excessive or insufficient clamping force.

[0021] 2. The flexible clamping device of this utility model causes less damage to the surface of the clamped object during the clamping process, and is particularly suitable for clamping fragile items with high surface precision requirements. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the flexible clamping device structure according to an embodiment of the present invention.

[0023] Figure 2 This is a structural diagram of the flexible gripper according to an embodiment of the present invention.

[0024] Figure 3 This is a circuit diagram of a filter amplifier according to an embodiment of the present invention.

[0025] In the diagram: 1-Flexible gripper, 101-Gripper body, 102-Gripper fingertip, 1021-Fingert fixing screw, 103-Piezoelectric film, 1031-Piezoelectric film terminal, 104-Pneumatic connector, 105-Fixing plate, 1051-Fixing plate screw, 2-Control system, 201-Controller, 202-Pneumatic source driver, 203-Filtering and amplifying circuit, 204-Power supply. Detailed Implementation

[0026] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0028] Example 1 is a flexible clamping device according to an embodiment of this utility model, such as... Figures 1-2 As shown, it includes: a flexible gripper 1 and a control system 2.

[0029] The flexible gripper 1 includes two symmetrically arranged gripper bodies 101. The bottom of the gripper body 101 is fixed on the fixing plate 105. The upper end of the gripper body 101 is provided with gripper fingers 102. A piezoelectric film 103 is attached to the outside of the gripper fingers 102.

[0030] The control system 2 includes a controller 201 and an air source driver 202 and a filter amplifier circuit 203 connected thereto, as well as a power supply 204 that supplies power to the controller 201, the air source driver 202, and the filter amplifier circuit 203. The driver outputs a drive signal to drive the gripper body 101 of the flexible gripper 1, which in turn drives the two gripper fingers 102 to move closer or further apart to achieve gripping or release. The filter amplifier circuit is connected to the piezoelectric film 103 on the outside of the gripper fingers 102 to collect the voltage feedback signal that characterizes the magnitude of the gripping force, and after processing, outputs it to the controller for closed-loop control.

[0031] Furthermore, the flexible gripper 1 structure includes: gripper fingertips 102, gripper bodies 101, a fixing plate 105, fixing plate screws 1051, an air connector 104, fingertip fixing screws 1021, and a piezoelectric film 103. The gripper bodies 101 are mounted on the fixing plate 105 via the fixing plate screws 1051, and the two gripper bodies 101 are symmetrically mounted. The two gripper fingertips 102 are respectively mounted on the two gripper bodies 101 via the fingertip fixing screws 1021. The piezoelectric film 103 is adhered to the gripper fingertips 102. The piezoelectric connector 104 is installed in a threaded hole on the gripper body. The gripper body 101 is a rubber cavity that can be inflated, sucked in air, or pressurized by natural air pressure. The gripper fingertips 102 are alloy sheets. When the rubber cavity is under natural air pressure, the gripper fingertips 102 are relatively separated. When the rubber cavity is sucked in air, the gripper fingertips 102 are relatively separated at a larger angle. When the rubber cavity is inflated, the gripper fingertips 102 are close together. As a specific example, the flexible gripper 1 is model SSL-1GN2521.

[0032] Furthermore, power supply 204 can be a switching power supply or a DC-DC power module, which converts 220V AC power into 24V DC power to supply the air source driver 202, 12V DC power to supply the controller 201, and 5V DC power to supply the filter amplifier circuit 203. The maximum power of the 24V DC load is 50W, the maximum power of the 12V DC load is 10W, and the maximum power of the 5V DC load is 5W.

[0033] Furthermore, the air source actuator 202 can be either active or passive. Active actuators do not require an external air source connection, while passive actuators do. The actuator 202 is model ACU2-H-0045, and the air source actuator 202 and the flexible gripper 101 are connected via a 4mm or 6mm inner diameter air tube and an air connection connector.

[0034] Furthermore, the controller 201 communicates with the air source driver via an RS485 serial port. The communication line uses a 2-core shielded twisted pair cable of 0.5 square millimeters or higher. Preset parameters include: setting the target positive pressure value for the gripper, setting the target negative pressure value for the gripper, positive pressure feedback acquisition signal, negative pressure feedback acquisition signal, positive pressure trigger signal, negative pressure trigger signal, and current gripper pressure acquisition signal. The controller 201 uses a single-chip microcomputer, specifically an STM32F405RGT6.

[0035] Furthermore, such as Figure 3 The diagram shows a filter amplification circuit according to an embodiment of this utility model. Terminals ADC1 and AGND are connected to the two ends of the piezoelectric film. Terminal ADC1 is also grounded via a TVS diode D1. Two voltage divider branches are connected in parallel between terminals ADC1 and AGND. Each voltage divider branch consists of two resistors connected in series: resistors R1 and R3, and resistors R2 and R4. A voltage signal is drawn between resistors R1 and R3, and between resistors R2 and R4. Both voltage signals serve as feedback input signals for operational amplifier U1, connected to its two input terminals 1IN+ (pin 3) and 1IN+ (pin 5), respectively. Operational amplifier U1's 1OUT (pin 1) and 1IN- (pin 2) are connected in parallel to output a CPU-ADC1 voltage follower signal. Operational amplifier U1's 2OUT (pin 7) and 2IN- (pin 6) are connected in parallel to output a CPU-ADC2 voltage follower signal. Both voltage follower signals are connected to the controller. Operational amplifier U1's VDD terminal is grounded via capacitor C1, and its GND terminal is grounded. The operational amplifier U1 is model AD8542ARZ, and the TVS diode D1 is model SMAJ5.0A.

[0036] The working principle of the filter amplifier circuit is as follows: TVS diode D1 protects the circuit voltage from exceeding 5V. ADC1 acquires the piezoelectric film voltage, which is then divided by resistors R1, R3 and R2, R4. The voltage value after division is followed by operational amplifier U1 for voltage tracking, and the processed voltage value is output to the controller from the CPU-ADC1 and CPU-ADC2 pins.

[0037] Working principle of the flexible clamping device in this embodiment of the utility model:

[0038] Because the piezoelectric film 103 is adhered to the outer surface of the gripper fingertip 102, deformation of the gripper fingertip 102 causes deformation of the piezoelectric film 103. This deformation of the piezoelectric film 103 results in a voltage change at its terminal 1031. The piezoelectric film terminal 1031 is connected to the filter amplifier circuit 203 via a two-core 0.5 mm² or larger shielded twisted-pair cable. The filter amplifier circuit 203 processes the voltage signal, characterizing the voltage change caused by the deformation of the gripper fingertip 102 under external pressure, resulting in the deformation of the piezoelectric film 103. When the piezoelectric film 103 is not deformed or is stationary after deformation, the output voltage of the piezoelectric film terminal 1031 is 2.5V.

[0039] When the air source actuator 202 outputs negative pressure, the gripper body moves inward, causing the gripper fingertips to move inward as well, closing and completing the gripping action. During the gripping action, the gripper fingertips bend outward, causing the piezoelectric film to bend outward. The piezoelectric film outputs a voltage of 0-2.5V, the output voltage value of which is determined by the bending speed during the bending process. The filtering and amplification circuit filters and amplifies the voltage at the piezoelectric film terminals in real time. The processor receives the voltage signal data processed by the filtering and amplification circuit in real time, records the voltage change during the bending process of the piezoelectric film, and obtains the gripping force through the voltage data. The gripping force can also indicate whether the gripped object has fallen.

[0040] When the air source actuator 202 outputs positive pressure, the gripper body moves outward, causing the gripper fingertips 102 to move outward, thus opening and completing the release action. During the release action, the gripper fingertips change from outward bending during clamping to returning to their normal curvature inward, causing the piezoelectric film 103 to return to its normal curvature. The piezoelectric film 103 outputs a voltage of 2.5-5V, the output voltage value of which is determined by the bending speed during the bending recovery process. The filter amplifier circuit 203 filters and amplifies the voltage at the piezoelectric film terminal 1031 in real time. The controller 201 receives the voltage signal data processed by the filter amplifier circuit 203 in real time, records the voltage change of the piezoelectric film 103 during the bending recovery process, and obtains the clamping force during the release process from the voltage data. The clamping force can also indicate whether the object has been placed completely.

[0041] During the gripping and releasing motion, the gripper tips deform, causing the piezoelectric film attached to them to deform as well. This deformation generates a voltage change across its terminals. A filtering and amplification circuit collects this voltage change, and the signal is processed through filtering and amplification. The controller then uses an ADC to collect the processed voltage signal as feedback for the gripping force and whether the object has fallen.

[0042] In the field of biology, this invention is used for holding and manipulating tissue samples; in the medical field, it is used for holding and manipulating tissues and organs; in the industrial manufacturing field, it is used for grasping and placing tiny precision devices; and in the agricultural field, it is used for gentle and accurate harvesting.

[0043] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the present utility model. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present utility model shall still fall within the protection scope of the present utility model.

Claims

1. A flexible clamping device, characterized in that, Includes a flexible gripper (1) and a control system (2); The flexible gripper (1) includes two symmetrically arranged gripper bodies (101). The bottom of the gripper body (101) is fixed on the fixing plate (105). The upper end of the gripper body (101) is provided with gripper fingers (102). A piezoelectric film (103) is attached to the outside of the gripper fingers (102). The control system (2) includes a controller (201) and an air source driver (202) and a filter amplifier circuit (203) connected thereto, as well as a power supply (204) for supplying power to the controller (201), the air source driver (202), and the filter amplifier circuit (203); the driver drives the two gripper fingers (102) of the flexible gripper (1) to move closer or further apart; the filter amplifier circuit is connected to the piezoelectric film (103) on the outside of the gripper fingers (102).

2. The flexible clamping device according to claim 1, characterized in that, The gripper body (101) is a rubber cavity, and the cavity is provided with an air connector (104). The air connector (104) is connected to the air source driver (202) through an air pipe.

3. The flexible clamping device according to claim 2, characterized in that, The air source driver (202) can be an active or passive air source driver.

4. The flexible clamping device according to claim 2, characterized in that, The gripper fingers (102) are alloy sheets that bend and deform when gripping an object.

5. A flexible clamping device according to claim 2, characterized in that, The filter amplifier circuit (203) includes: terminals ADC1 and AGND are connected to the two ends of the piezoelectric film (103), terminal ADC1 is also grounded through TVS diode D1, two voltage divider branches are connected in parallel between terminal ADC1 and AGND, and two voltage signals are respectively led out from the two voltage divider branches and connected to the two input terminals 1IN+ and 1IN+ of operational amplifier U1; the parallel connection of 1OUT and 1IN- of operational amplifier U1 outputs the CPU-ADC1 voltage follower signal, the parallel connection of 2OUT and 2IN- of operational amplifier U1 outputs the CPU-ADC2 voltage follower signal, and the two voltage follower signals are connected to the controller (201); the VDD terminal of operational amplifier U1 is grounded through capacitor C1, and the GND terminal is grounded.

6. The flexible clamping device according to claim 5, characterized in that, Each voltage divider branch of the filter amplifier circuit (203) is composed of two resistors connected in series: resistors R1 and R3 are connected in series, and resistors R2 and R4 are connected in series.

7. A flexible clamping device according to claim 5, characterized in that, The piezoelectric film (103) is provided with a terminal (1031), which is connected to the terminals ADC1 and AGND of the filter amplifier circuit (203).

8. A flexible clamping device according to claim 5, characterized in that, The controller (201) is a microcontroller; the power supply is a DC-DC module that provides +12V power to the controller (201), +24V power to the air source driver (202), and +5V power to the filter amplifier circuit (203).

9. A flexible clamping device according to any one of claims 1-8, characterized in that, The flexible gripper (1) is mounted on the fixed plate (105) by a fixing plate bolt (1051); the gripper fingers (102) are mounted on the gripper body (101) by finger fixing bolts (1021).

10. A flexible clamping device according to any one of claims 1-8, characterized in that, The bottom fixing plate (105) of the flexible gripper (1) of the flexible clamping device is also fixed to the end of the robotic arm by bolts. The movement of the robotic arm drives the flexible clamping device to move to the vicinity of the target object to be clamped.

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